import math
import json

class Shape:
    def area(self):
        raise NotImplementedError

class Triangle(Shape):
    def __init__(self,base,high):
        self.base = base
        self.high = high
    def area(self):
        return self.base * self.high / 2
class Rectangle(Shape):
    def __init__(self,longth,width):
        self.longth =  longth
        self.width = width
    def area(self):
        return self.longth * self.width
class Cicle(Shape):
    def __init__(self,radius):
        self.radius = radius
    def area(self):
        return math.pi * (self.radius ** 2)

class MixinSerializeArea:
    def serialize_area(self):
        print('{}的面积是{:.2f}'.format(SerializeCicle.mro()[2].__name__,self.area()))

class SerializeCicle(MixinSerializeArea,Cicle):
    pass

a = SerializeCicle(5)
a.serialize_area()

